Temporal Variation In Activity Research Articles

Progress and landscape of disaster science: Insights from computational analyses

This study identifies trends in disaster science research as well as knowledge gaps at a broad scale in order to help underpin and inform future research in the area. A numerical analysis of 58,106 peer-reviewed articles over four decades reveals key research themes and clusters, their temporal variation of activity as well as the influential studies that have played a key role in their development. Results indicate that what we recognize as contemporary disaster science has only shown discernible patterns of activity and knowledge foundation formation since the 1990s. Disaster research currently constitutes approximately 0.23% of all academic papers published per year. The initial and intermediate phases of the development of the field have been unsystematic and fragmented, with the focus of the field fluctuating for almost two decades until recently when research clusters have shown signs of stabilizing. It is observable that, over the last few years, more attention has been allocated to mitigation, response and recovery by focusing on issues such as the psychological impacts of disasters, reducing exposure to disasters and building community resilience to cope and recover from disasters. This is in contrast with earlier years where the focus was predominantly on preparedness and prevention. Research in different countries has been highly correlated with the types of disasters that occur in their regions, highlighting the relevance of the local situatedness and context in disaster research. The recent emergence and explosive growth of a research cluster linked to flood detection, flood mapping and flood hazard assessment is particularly notable, marking the sharpest growth of a single research cluster ever recorded in this field. A similar trend, though of a smaller magnitude, is observable in relation to research on wildfire hazard. Overall, flood-related research has proven one of the dominant themes, with multiple clusters detectable on the topic, each with their own distinguishable knowledge foundation (i.e., set of references). The pattern of collaboration among disaster researchers is shifting from predominantly domestic research towards international collaborations (currently reaching about 1/3 of all disaster-related papers each year), a sign of recognition to the value of cross-cultural and interdisciplinary perspectives in disaster research.

Vertical and temporal variations in activity, abundance, and composition of nitrite-driven anaerobic methanotrophs in a paddy field

Paddy soil is an important source of methane (CH4) emissions, and the nitrite-driven anaerobic oxidation of methane (AOM) mediated by Candidatus Methylomirabilis bacteria is a crucial process for CH4 mitigation. However, the vertical and temporal fluctuations in nitrite-driven AOM activity, as well as the abundance and composition of Methylomirabilis bacteria in paddy soil, remain poorly understood. We investigated the potential rate of nitrite-driven AOM and the composition of Methylomirabilis bacteria at varying depths (0–40 cm, at 10 cm intervals) within a paddy soil during different growth stages of rice, including tillering, jointing, flowering, and milky. The potential rate of nitrite-driven AOM ranged from 0.24 to 20.6 nmol CO2 g−1 (dry soil) d−1, and the abundance of Methylomirabilis bacterial 16S rRNA genes varied from 5.8 × 106 to 4.4 × 107 copies g−1 dry soil. The 10–20 cm soil depth showed higher potential activity and bacterial abundance compared to other depths, and the tillering and jointing stages exhibited greater activity and abundance. The composition of Methylomirabilis bacteria showed significant variation across different soil depths but remained stable throughout the growth stages of rice. Soil organic carbon content was positively correlated with potential nitrite-driven AOM rate, and nitrite content was negatively correlated with the abundance of Methylomirabilis bacteria. Soil organic carbon and ammonium content had a significant impact on the composition of Methylomirabilis bacteria. The results underscore the substantial influence of soil depth and the growth stage of rice on nitrite-driven AOM in paddy ecosystems.

Effect of switching time scale of receptor activity on chemotactic performance of Escherichia coli

In the chemotactic motion of Escherichia coli, the switching of transmembrane chemoreceptors between active and inactive states is one of the most important steps of the signaling pathway. We study the effect of this switching time-scale on the chemotactic performance of the cell. We quantify performance by the chemotactic drift velocity of the cell. Our extensive numerical simulations on a detailed theoretical model show that as the activity switching rate increases, the drift velocity increases and then saturates. Our data also show the mean duration of a downhill run decreases strongly with the switching rate, while that of an uphill run decreases relatively slowly. We explain this effect from temporal variation of activity along uphill and downhill trajectories. We show that for large and small switching rates the nature of activity variation show qualitatively different behaviors along a downhill run but similar behavior along an uphill run. This results in a stronger dependence of downhill run duration on the switching rate and relatively milder dependence for uphill run duration.

Temporal complementarity in activity‐density of two arthropod macro‐detritivore taxa

Abstract Macro‐detritivores are important fragmenters performing a first step in the ecosystem process of nutrient cycling. Woodlice and millipedes are important representatives of this group and their ecology and niche requirements are often regarded as very similar. However, it is unclear whether there is a difference in temporal activity throughout the year between both groups, possibly leading to temporal complementarity for leaf litter breakdown, and whether patterns of temporal variation in activity are consistent across different habitat types. We studied year‐round pitfall‐trap data of woodlice and millipedes from an old sand quarry with a high habitat heterogeneity. Our results indicate that there is high temporal complementarity between both detritivore taxa, with millipede activity‐density peaking in spring, while woodlice showing a peak in summer. Interestingly, timing of activity depended on habitat openness. Millipedes peak first in open habitat and later in closed habitat, while woodlice showed the opposite pattern. Temporal turnover in community composition was high and of similar magnitude as spatial turnover in community composition across this relatively small scale of our study area. We conclude that, although woodlice and millipedes show comparable habitat preferences, their temporal activity patterns show the potential for temporal complementarity for litter breakdown.

Temperature explains variation in seasonal temporal activity of Miniopterus natalensis more than moonlight or humidity

Animals partition their daily activities based on a variety of internal and external factors. For insectivorous bats, the availability of prey, weather conditions, moonlight and reproductive energy demands are proposed as the major influencers of temporal activity. This study investigated the temporal variation in activity of the subtropical cave-dwelling, migratory Natal long-fingered bat, Miniopterus natalensis, by temperature, humidity, lunar illumination and the time of moonrise per night. Using echolocation survey data collected 2014–2018 near a maternity roost in north-eastern South Africa, differences in activity between the summer maternity (1 September–28 February) and winter non-breeding (1 March–31 August) seasons were described. In the non-breeding season, M. natalensis exhibited peak activity during the early evening, with decreasing activity throughout the night. In the maternity season, a bimodal activity pattern was observed, probably related to peaks in insect activity and the energy requirements of lactating females. Predictably, temperature had the strongest positive influence on the magnitude of M. natalensis activity across both seasons. Humidity also positively affected activity in both seasons to a lesser extent. The time of moonrise did not affect the activity of M. natalensis during either of the seasons. Lunar illumination did not affect activity during the maternity season, but activity was diminished on nights with bright moonlight in the non-breeding season. Emergence and return times were not affected by lunar illumination in either season. The need of M. natalensis to maximise resource acquisition during the maternity season is likely a strong modulator in the temporal activity of this species and outweighs predation risk in high moonlight conditions. Subsequently, this species exhibits nightly activity behaviours that balance risk factors with intrinsic needs during different seasons.

Activity Rhythms of Coexisting Red Serow and Chinese Serow at Mt. Gaoligong as Identified by Camera Traps.

Simple SummaryHow congeneric species with similar realized niches manage to coexist is a central question in the study of biodiversity. Here, we examined the daily activity rhythm of two coexisting serow species in a mid-mountain humid evergreen broadleaf forest. We used camera traps in a five-year survey at Mt. Gaoligong, western Yunnan, China. We compared the daily activity rhythm of the rare red serow (Capricornis rubidus), a medium-sized solitary ungulate, with the coexisting Chinese serow (C. milneedwardsii milneedwardsii). Although their overall daily activity rhythms were similar, the rare red serow tended to range, feed, and stay vigilant from afternoon through midnight throughout the year. By contrast, Chinese serows preferred to be active from sunrise to noon in the wet season, but shifted their activities and behaviors to afternoon and midnight in the dry season. Interestingly, we found red serows sometimes ranging together with Chinese serows. When they encountered each other, red serows altered their activity patterns more notably, while Chinese serows significantly increased their activity level. These findings are understandable given their similar resource requirements. Although exploitative competitors, red and Chinese serow coexist by avoiding interference competition by altering their respective activity patterns in time.Surveying the activity rhythms of sympatric herbivorous mammals is essential for understanding their niche ecology, especially for how they partition resources and their mechanisms of coexistence. Over a five-year period, we conducted infrared camera-trapping to monitor the activity rhythms of coexisting red serow (Capricornis rubidus) and Chinese serow (C. milneedwardsii milneedwardsii) in the remote mountainous region of Pianma, Mt. Gaoligong, Yunnan, China. Cameras captured images of red serow and Chinese serow on 157 and 179 occasions, respectively. We used circular kernel density models to analyze daily activity rhythms and how temporal variations in activity ensure their co-existence. Although their overall activity levels and patterns were similar, temporal activity and behavior partitioning among the two species occurred during the wet season. Compared with Chinese serows, red serows exhibited less variable daily activity levels, patterns, as well as feeding and vigilance behaviors between seasons. When the two species occasionally ranged together, red serows tended to alter their activity pattern while Chinese serows significantly increased their activity level. Red serow and Chinese serow are exploitative competitors but coexist by altering their daily activity rhythms when in contact and changing activity patterns during the wet season, enabling their coexistence.

Detection Probability of Bats Using Active Versus Passive Monitoring

As technology has evolved, bat researchers have relied more heavily on using acoustic techniques to collect data on bat communities. Acoustic data can be collected actively, where the researcher is present at the sampling point and follows the bat with the detector, or passively, where the researcher is not present and the detector is set out by itself. Active sampling can yield longer, clearer calls, and is only conducted during part of the night (usually from sunset to about 02:00 hours) for short bouts (20 minutes). By contrast, passive sampling can yield lower quality calls, but procedures are easily repeatable and data can be used to measure temporal variation in activity throughout the night and detect individuals and species that are missed during active sampling. Researchers are increasingly attempting to monitor and compare bat communities over time, including sites where both active and passive sampling have occurred. However, these two techniques can yield different detection probabilities and the extent to which data collected using these two techniques can be compared is unclear. Thus, in July 2017 we simultaneously collected acoustic data actively and passively to compare detection probabilities of bats at the Savannah River Site, South Carolina, USA. Using Anabat Express detectors, we detected five species or species groups (Eptesicus fuscus/Lasiurus cinereus, L. borealis/L. seminolus, Perimyotis subflavus, Myotis austroriparius, and Nycticeius humeralis) using each method. Using single season occupancy modeling, we found that method (passive vs. active sampling) had a significant effect on detection probabilities of all species, and that passively sampling throughout the night yielded the highest detection probability for all species. As a result, if differences in detection probability are not taken into account, comparison of historical active datasets with current passive datasets could lead to different insights into habitat use by similar bat communities. Based on our findings, we recommend that researchers use passive sampling throughout the night when studying and monitoring bat communities.

Modeling Temporal Variation in Physical Activity Using Functional Principal Components Analysis

Accelerometers are person-worn sensors that provide objective measurements of movement based on minute-level activity counts, thus providing a rich framework for assessing physical activity patterns. New statistical approaches and computational tools are needed to exploit these densely sampled time-series data. We implement a functional principal component mixed model approach to ascertain temporal activity patterns in 578 overweight women (60% cancer survivors) and summarize individual patterns with unique personalized principal component scores. We then test if these patterns are associated with health by performing multiple regression of health outcomes (including biomarkers, namely, insulin, C-reactive protein, and quality of life) on activity patterns represented by these scores. Our model elucidates the most important patterns/modes of variation in physical activities. Results show that health outcomes including biomarkers and quality of life are strongly associated with the total volume, as well as temporal variation in activity. In addition, associations between physical activity and health outcomes are not modified by cancer status. Our findings suggest that employing a multilevel functional principal component analysis approach can elicit important temporal patterns in physical activity. It further allows us to study the relationship between health outcomes and activity patterns, and thus could be a valuable modeling approach in behavioral research.

Interpretation of recent alpine landscape system evolution using geomorphic mapping and L-band InSAR analyses

Alpine landscapes are typically characterized by inherited features of past glaciations and, for the more recent past, by the interplay of a multitude of types of geomorphic processes, including permafrost creep, rockfalls, debris flows, and landslides. These different processes usually exhibit large spatial and temporal variations in activity and velocity. The understanding of these processes in a wide alpine area is often hindered by difficulties in their surveying. In this study, we attempt to disentangle recent changes in an alpine landscape system using geomorphic mapping and L-band DInSAR analyses (ALOS-PALSAR) in the Zermatt Valley, Swiss Alps. Geomorphic mapping points to a preferential distribution of rock glaciers on north-facing slopes, whereas talus slopes are concentrated on south-facing slopes. Field-based interpretation of ground deformation in rock glaciers and movements in talus slopes correlates well with the ratio of InSAR images showing potential ground deformation. Moraines formed during the Little Ice Age, rock glaciers, and talus slopes on north-facing slopes are more active than landforms on south-facing slopes, implying that the presence of permafrost facilitates the deformation of these geomorphic units. Such deformations of geomorphic units prevail also at the elevation of glacier termini. For rock cliffs, the ratio of images indicating retreat is affected by slope orientation and elevation. Linkages between sediment supply from rock cliffs and sediment transport in torrents are different among tributaries, affected by relative locations between sediment supply areas and the channel network. We conclude that the combined use of field surveys and L-band DInSAR analyses can substantially improve process understanding in steep, high-mountain terrain.

Camera Traps are an Effective Tool for Monitoring Lewin's Rail (Lewinia pectoralis brachipus)

Abstract. Precise sampling and observational techniques are fundamental to the management and conservation of many bird species. An array of camera traps (n = 15) was deployed to collect information on a poorly known wetland bird, Lewin's Rail (Tasmanian) (Lewinia pectoralis brachipus) on Tasman Island, Australia, from 25 August 2012 to 10 June 2013. Using camera traps located to maximize detection probability, images from 1,213 camera events quantified Lewin's Rail occurrence and temporal variation in activity. Observations of social organization and behavior, agonistic behavior, foraging, relations within family groups, breeding activity, and diel activity were recorded. Lewin's Rail behavior was documented for a total of 294 days (n = 3,975 camera trap days). This study demonstrates the effectiveness of camera traps as a tool for studying secretive ground-dwelling birds. Although camera traps cannot replace other avian survey methods, they provide a complementary method for collecting behavioral data o...

Temporal variations in activity patterns during rut – implications for survey techniques of red deer, Cervus elaphus

Context Intraspecific differences in behaviour can affect censuses and bias population estimates, suggesting that choice and implementation of census methods are fundamental, and need to be adapted to behavioural variations. Aims We investigated temporal variations in activity patterns during the rut among red deer (Cervus elaphus) categories and the implications for two different census methods. Methods We used a long-term dataset collected during 17 consecutive red deer rutting seasons in southernmost Sweden. The two census methods were: (1) a collection of observation ratios; and (2) a count of individuals including identification of males. Both methods are commonly used in ungulate management. Key results There was a difference in activity among age and sex categories, with a temporal variation in activity and/or presence at rutting grounds of adult (≥6 years) and subadult (2–5 years) males. Observation ratios of adult and subadult males increased from low at the start of the rut to a top level during peak rut, with subadults lagging behind adults. Before and during peak rut, the proportion of adult males was higher than that of subadults. After peak rut, the proportion of adult males decreased, whereas subadult males remained high, resulting in a higher number of subadults than of adults. The comparison of the two census methods revealed a strong correlation regarding the trends of population size and for the age and sex categories. There was also a strong consistency concerning the calf/female ratio. The male proportion was, however, consistently lower in the collected observations than in the counts. Conclusions The lower proportion of males in observations compared with counts may be explained by behavioural differences among male age classes, i.e. by temporal variations in presence and activity. That females, calves and yearling males are stationary during the rut, but adult and subadult males arrive and depart the rutting grounds at varying points of time, can lead to an underestimated male proportion in continuously collected observation data. Implications The results suggest that census should be conducted during peak rut, and that incorporating identification of individual males in the monitoring may be beneficiary.

Effects of site, time, weather and light on urban bat activity and richness: considerations for survey effort

To maximise bat retention in urban environments, efficient bat monitoring is needed, but the factors that influence survey results for urban bats are unclear. We used echolocation call detectors (n = 378 detector-nights from November 2005 to October 2006) to assess bat activity among different sites in the Adelaide City parklands, temporal variations in activity (hourly, nightly, monthly), and responses to weather and light (artificial and moon). Bat species did not occur evenly in urban conditions; dark parks were more important for bat diversity and activity (six species groups in the darkest park) than were artificially lit parkland areas (three species groups in the flood-lit park). Gould’s wattled bat (Chalinolobus gouldii) and Mormopterus species 4 (94% of calls) were advantaged in urban parklands, being the only species recorded when lights were on at sports parks, whereas five species groups occurred when the lights were off. Minimal bat activity was recorded in the first 2 h after civil twilight, suggesting that bats may roost outside the city and commute nightly into parklands. Bat activity increased with temperature, with a burst in activity occurring after 7°C. Rainfall (>1 mm/24 h) and moon illumination at midnight did not influence activity. Urban environments should provide diversity to attract a diverse assemblage of bat species. Activity fluctuated among sites, nights, and across the year, indicating that large sample sizes over long periods of time are required to monitor and survey bats reliably with detectors.

Breeding biology of Physalaemus centralis Bokermann, 1962 (Anura: Leptodactylidae) in southeastern Brazil

Physalaemus centralis is widely distributed in areas of cerrado vegetation in South America. Here we describe the temporal variation in activity and explore eventual effects of climatic conditions on activity, calling sites, territorial behaviour; courtship behaviour, egg clutches and tadpole development of P. centralis in southeastern Brazil. Field observations were made from January 1996 to February 1997. Vocalisations and reproductive activity were restricted to the rainy season, with a peak of activity in October. The number of calling males was significantly correlated with relative humidity, mean air temperature, and air pressure values of the previous day. Courtship is simple and did not include any physical contact before amplexus; furthermore, females seem to choose their mates. Amplectant pairs were observed from mid‐October to mid‐December. Most foam nests observed were anchored within the vegetation. The number of eggs in the foam nests ranged from 1549 to 2405. Tadpoles were mainly found in shallow parts of the water from October to mid‐January. The reproductive biology of P. centralis is similar to that of closely related species of the P. cuvieri group, suggesting conservatism in this lineage.

Diel flight activity and ecological segregation within an assemblage of tropical forest dung and carrion beetles

Temporal variation in activity of dung and carrion beetles in tropical forest is considered as a mechanism of ecological segregation between potentially competing species. We describe the diel flight activity of Scarabaeidae collected with baited pitfall traps at Les Nouragues field station in French Guiana. A total of 2663 individuals of 63 species was recorded, from the subfamilies Coprinae, Scarabaeinae and Aphodinae. Temporal guilds of diurnal, nocturnal and crepuscular species were identified. Diurnal species were about twice as numerous and abundant as either nocturnal or crepuscular species. Two main activity patterns characterize the diurnal species while nocturnal and crepuscular species show overlapping activity. The association of activity rhythm with the other niche variables, food selection, functional group, body size and relative abundance, was analysed using multiple correspondence analysis. Small diurnal coprophagous species were opposed to large crepuscular necrophagous species. Species packing is suggested but further analysis showed that the variables were independent of one another. The temporal differentiation of species combined with separation along multiple niche dimensions and resource gradients may facilitate the coexistence of species assumed to be strongly affected by interspecific competition.

Temporal Variation in Activity of Bats and the Design of Echolocation-Monitoring Studies

I used Anabat II bat detectors to monitor echolocation calls of bats over two streams in the Oregon Coast Range for a total of 195 detector-nights. Activity of bats was positively correlated with biomass of insects and minimum nightly temperature, and was negatively correlated with length of night; activity levels at the two streams were positively correlated. Activity of bats was not significantly correlated with either hours of moonlight or with phase of moon. Level of activity within a night generally peaked shortly after sunset with a second, smaller peak in activity shortly before sunrise, but patterns varied substantially among nights. Total nightly activity at a site also varied substantially among nights, sometimes varying several-fold on consecutive nights. To assess the implications of temporal variation in activity of bats on sampling, I randomly sampled subsets of the data using from 2- to 12-night sample periods and calculated mean levels of activity for each subset. For subsets with seven or more nights, >60% of the subsets had means that were within 20% of the mean of the entire dataset. Less than 50% of the subsets had means within 10% of the mean of the entire dataset for any number of nights subsampled. When comparing activity between sites, use of blocked or paired designs improved sampling efficiency by 20%. Failure to account for temporal variation in activity of bats when designing research projects and monitoring programs could result in biased estimates of activity of bats.

Cellulase activity of leaf litter and stream-dwelling, shredder macroinvertebrates

The magnitude and temporal variability of exocellulase (β-1,4-exoglucanase) activity in leaf litter and guts of shredding macroinvertebrates was determined over one year in four streams in Virginia, USA. The streams flowed in three physiographic provinces and hence varied as to geomorphology, hydrology, water chemistry and riparian landscape. No significant difference in exocellulase activity occurred between streams over the year. Considerable temporal variation in activity did occur in all streams, with peaks in autumn-early winter and again in spring, corresponding to the primary periods of input of fresh allochthonous organic matter. Litter bag studies showed that peak exocellulase activity occurred after about one month of processing. Exocellulase activity in the guts of shredders was generally correlated with activity in their detrital food, suggesting that gut enzyme activity was acquired.